Heavy naphtha as a sponge oil



Oct. 20, 1959 J. 1 PA'rToN ETAL HEAVY NAPHTHA AS A SPONGE OIL Filed March '7, 1956 nm. Q:

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INVENTORS MARTIN NON INPE-Jam mZulTfX QN. Iwmtowm( a9 lv R. SMITH JAMES L. PATTON N ATTORNEYS United States Patent() 2,909,419 HEAVY NAPHTHA As sPoNGE orL James L. Patton, Ramsey, and MartinvR. Smith, Glen Ridge, NJ., assignors to The M. W. Kellogg Company, Jersey City, NJ., a corporation of Delaware Application March 7, '1956, Serial No. 570,055 i 9 Claims. (Cl. 20S- 102) 2,909,479 Patented Oct. 20, 1959 ice flowing liquid naphtha stream introduced at thetop of the column. The naphtha, commonly referred to as a sponge oil absorbs the lean oil constituents contained inthe tail gases and is withdrawn from the bottom of the tower. The tail gases are removed from the `top of the column and utilized in the process. Instead of theheavy naphtha, a post-aviationv gasoline fraction, 1 29.0 A.P.I

gravity, which is a product of the hydrofor'ming process should be obtained, each of which isv a pure compound and the full amount of each component of lnhe original charge should be so'separated. However, theI vapor generated from a poly component liquid is in no case that of the most volatile component alone. Consequently, no actual l distillation process achieves the. perfect separation, and

the components of the distillant overlap across any series of distillates, however small the fractions be taken. In manyinstances, the small amounts of less desired components obtained with a desired distillate fraction have no effect on its intended use. In the event these components cannot be tolerated or their recovery is desired,'many elaborate treating processes have been devised. The purpose of the present inventiomhowever, is'to provide a simple economical and integrated process `for the recovery of desired componentsnormally lost from the process. More specifically, the present invention is directed to the recovery of valuable lean oil constituents found in vhydroformate tail gases which would be normally lost tothe producer.

An object of this inventionds to recover valuable lean oil `products in recycletail gas.`

A second object of this invention is to provide a process wherein products of a hydroforming process are used-'to absorb valuable lean oil constituents from the recycle' tail gases. Y

Various other objects and advantages of the present invention will become apparent to'those skilled in' theart from the accompanying description and' disclosure.V

According tothe improved process of -the present invention, a heavy naphtha,f5060 A.P.I. gravity from-a hydroformng feedpreparation unit is passed countercurrently to Vhydroformate tail gases in an absorption column .to recover'valuable lean oil constituents entrained in the tail gases. The amount of lean oil constituents usually contained in the tail gases is between about 3 to about l0 weight percent. V For best operation,` the absorber tower is operated in a temperature range of about'110" F. to about 150 F. under a pressure of`approximately 220 pounds gauge. The hydroformate tail gas stream is introduced into the bottom of the absorber tower and passes upwardly in countercurrent contact with the downwardly may be used as the sponge oil to separate the lean oil constituents from the tail gases. Y

- Generally, the naphtha sponge oil is introduced to the top of the tower at a temperature of approximately 100"l F. and the heat or temperaturerequirements of the column is usually maintained by the use of a relatively hot tail gas stream introduced to the bottom of the column. During the absorption, heat is liberated and the problem sometimes encountered is that of removing this heat of solution of the absorbed components by cooling means. w

The tail gases separated of its lean oil constituents and having a molecular-weight of approximately 10.8 is then passed to a stripping zone to separate absorbedoxygerl in a naphtha feed for the' hydroforming reaction. The

amount of oxygen usuallyY contained in the naphtha feed` obtained from storageis between about 0.1 andabout 3 weight percent. The removal of absorbed oxygen in the naptha feed is particularly desirable to prevent the formation of any resinous compounds in the feed during heating to reaction temperature. Y Y 4 After pretreating the feedV and heating to the desired reaction temperature, approximately 850-l050 F., the naphtha feed is passed through a hydroforming conversion zone in the presence of added hydrogen and in the lpresence of a conventional hydroformingcatalyst, such as molybdenum or platinum supported on a suitable carrier material such as alumina. The hydroforrning reaction is v carriedoutat a temperature of about 875 to about 975"v F;

at a pressure betweenabout 50 and about 500 pounds per square inch gauge. Under such conditions of temperature, pressure and hydrogen concentration, the naphtha feed is y converted to a..product having a substantially increased octane value.l The eluent from the hydroforming reaction is then passed to suitable recovery equipment for recovering various desired petroleum fractions such as an aviation gasoline fraction and a heavier aviation base fraction. Ultimately; a tail gas is recovered from the equipment comprising a series of distillation operations which is treated andused as previously described. i

It is believed that the present invention mayA be, best described by reference to the accompanying -drawing which shows the inventive features of the present invention as applied, for example, to the recovery of valuable products from tail gases or recycle gases and the use of tail Vgases to prepare a naphtha feed for ahydroforming conversion process. Y The drawing is a diagrammatical illustration in eleva-4 tion of an arrangement of apparatus for the'separation of hydroforrnate products and the recovery of valuable lean oil constituents from recycle or tail gases. Referring tothe drawing, a naphtha feed, 55.0 A.P.I. gravity con# taining absorbed oxygen is introduced through conduitv 12'at a rate of approximately 191,000 pounds per hour,

pump 14, and conduit 16 to the top of feed stripper column by conduit 250 and passed to a separator 254 then through conduit 256 to the bottom of preheater 220 to be used as fuel gases in the furnaces. Additional fuel gas may be added to conduit 250 by conduit 252. The stripped naphtha feed is removed from the bottom of feed stripper at atemperature in the range of 120-190 F. through conduit 20 and passed through pump 22 to conduit24 and then to heat exchanger 34 wherein the temperature of the feed is raised to approximately`3r50 F. prior to entering preheatrfurnace 38 by conduit 36. Heat exchanger 34 may obtain heat from any of the hot products of the process. In heat exchanger 34 the `fresh naphtha feed stripped of oxygen is preheatedto a temperature sufficient to eliminate the corrosive action'on the outside of the heater tubes within preheater`38 as previously experienced and described above. In ypreheater 38 the temperature of the feed is raised to approximately 950 F. and thenpassed through conduit 40 to a conventional hydroforming reactor 42 wherein the Vfeed is converted to desirable cyclic cornpounds ofhigher octane rating in the presence of a hydroforming catalyst. In addition to the feed introduced to the bottom of reactor 42 by conduit 40, a sufcient quantity of recycle gas, predominantly hydrogen, obtained from the process hereinafter described is introduced'by conduit 112 to preheating furnace 114 wherein thetemperature is raised to approximately 1000 F. and then passed through conduit 116 at a rate of approximately 148,000 pounds per hour into the bottom of the hydroforming reactor. 42. The hot products of reaction are removed from the top of the reactor at a temperature of approximately 915 F. by conduit 44 passed through heat exchanger 46 wherein the temperature is reduced to approximately 750 F. and conduit 48 to a plurality ovfheat exchangers 50 where the temperature is further reduced to aprpoximately 480 to 540 F. then through conduit 52 to the bottom of a fractionation and separation tower 56. lIn heat exchangers 50 the hydroformate products from reactor 42 are materially reduced in ternperature approximately 300 F. prior to,k introduction into fractionator separator 56. The hydroformate products in heat exchangers 50 give up their sensible heat to bottoms withdrawn from de-ethanizer 100 and depentanizer 120 which will bedescribed hereinafter. In fractionator separator 56 operated at a temperature range of approximately 250 to 300 F. and a pressure of approximately 245 pounds gauge, the hydroformate products free of entrained catalyst fines are removed through conduit 70 at a rate of approximately 485,000 pounds per hour to cooler 72 then to separator 74 maintained at a temperature of approximately 105 F. and a pressure of 235 pounds gauge wherein the hydroformate products are separated into a normally gaseous stream and a liquid stream. The liquid stream, 56.3 A.P.I. gravity, is withdrawn through conduit 76 ata rate of approximately 310,000 pounds per hour to pump 80, and a portion of the liquid stream, approximately 155,000 pounds per hour, is returned to the top of fractionator separator 56 by conduit 78. In fractionator separator 56 entrained catalyst fines contained in the hydroformate product are removed from the product and withdrawn to the bottom of the zone into a settling chamber 54 in the lower part of fractionator 56. The catalyst iines may be returned to the reactor 42 as desired through conduit 182. In separator 74 the gaseous products are withdrawn through conduit 86 at a rate of approximately 169,000 pounds per hour to a dry separator 104 maintained at a pressure of 234 pounds gauge and a temperature of approximately 105 F. A portion of the gaseous product is returned to V4 Y the reactor 42 at a rate of approximately 137,000 pounds per hour by conduit 108, pump 110, and conduit 112 as previously described. Another portion of the gaseous product in conduit 86 is withdrawn at a rate of approximately 30,000 pounds per hour through conduit 88 and passed to the lower portion of de-ethanizer tower 100. In addition, a portion of the decanted liquid product withdrawn from the bottom of fractionator 56 at a rate of approximately 7,000 pounds per hour and a temperature of approximately 350 F. is passed through conduit 84 containing approximately all of the polymer produced in the hydroforming reactor 42 and consisting primarily of gasoline to the lower portion of the de-ethanizer tower by conduit 84 and 90. A portion of the liquid product in separator 74'withdrawn by conduit 76 is passed through yconduit 82 at a rate of approximately 155,000 pounds per hour into the upper portion of d e-ethaniz'er tower 100. De-ethanizer tower 100 is operated under Vtemperature conditions in the range of 110 to 400 F. and at a pressure of approximately 210 to 230 pounds gauge. A low boiling fraction primarily tail gases, molecular weight 12.3, is withdrawn from the top of de-ethanizer tower 100 by conduit 122 at a rate of approximately 28,000 pounds per hour which product contains a low percentage (about 3 to 10 weight percent) of lean oil products, and is passed to the bottom of absorber tower 124 in countercurrent contact with a heavy naphtha fraction 50.6 A.P.I. gravity introduced to the top of tower 124 by conduit 26 for the purpose of absorbing the lean oil constituents from the predominantly gaseous fraction introduced to the bottom of absorber 124. The enriched heavyv naphtha sponge oil is then withdrawn from the bottom of absorber tower 124 at a rate of approximately 24,000pounds per hour through conduit 142 to'separator 150 operated at a temperature of approximately 200 F. and a pressure of approximately 10 pounds gauge. The rich'sponge oil is withdrawn from thebottom ofseparator 150 through conduit 152, pump 154, and conduit 156 to rich sponge oil storage. The gaseous products stripped of their lean oil constituents havinga molecular weight of approximately 10.8 are rcmovedfrom the top of absorber tower 124 at a rate of approximately 750.pounds per hour by conduit 128 and passed to feed stripper 10 for the purpose of stripping oxygen from the. naphtha feed as previously described. The normally liquid products, 49.5 A.P.I. gravity, in the bottom of de-ethanizer tower is withdrawn from lthe 'bottom of the column by conduit 130 at a'rate of approximately 256,000 pounds per hour and passedto depentanizer by conduit 130. yA-portion of this liquid product'may be diverted through conduit 132 and pump 134 to a heat exchanger 136 and-back into the bottom of the-column through conduit '141 containing cooler or through conduit 138. As previously described, heat exchanger 136 may be used as one of the heat exchangers 50 in the hydroformate effluent conduit 48 for the purpose of reducing the temperature of the hydroforrnate efiluent and increasing the temperature of the de-ethanizer bottoms being circulated to the bottom of the de-ethanizer column. Any liquid products .recovered in dry separator 104 may be withdrawn through conduit 118 and admixed with deethanizer bottoms in conduit 130 prior to entering depentanizer-column'120. In depentanizer column 120 a propane-butane-pentanecut 10.8 A.P.I. gravity is removed fromrthe top -column by conduit 180, cooler 182, and separator 184 maintained at a temperature of approximately 135 F. and a pressure of approximately 100 pounds gauge. A portion'of this fraction is returned by conduit 186, pump 188, and conduit to tbe top of the depentanizer column. Another portion of Vthis cut is withdrawn through conduit 186, pump 188v and conduit 192 at a rate of approximately 29,000 pounds per hour and sent to storage. A higher boiling fraction separated in depentanizer tower 120 which is operated at a temperature range of 180 to 410 F. and a pressure of approximately 115 pounds gauge is'withdrawn from the bottom of the column through conduit 160. A portion of this fraction may be passed through conduit 170,

.-reduced in temperature to about 105 F. inheat exchanger 144 and passed through `conduit 162 to the top of the de-ethanizer tower 100 at ar rate of approximately 93,000 pounds per hour as reflux. A third portion of the bottoms, 41.5 A.P.I. gravity, from the depentanizer tower 120 lWithdrawn lthrough conduit 160 is. diverted at a rate of approximately 13,500 pounds per hour through conduit 164 to tower 168 referred to as a gasoline splitter tower. In tower 168 a low boiling fraction referred to as a pre-aviation gasoline cut, 59.3 A.P.I. gravity, is withdrawn through conduit 204 to cooler 206 and separator 208 maintained at a temperature of approximately 220 F. and a pressure of approximately 15 pounds gauge. A portion of this fraction is returned as reflux to the top of tower 168 at a temperaturerof 2,20 F Ithrough conduit 210, pump 212, and conduit 214 at a rate of approximately 186,000 pounds per hour. Another portion is withdrawn through conduit 216 to storage at a rate of approximately 38,000 pounds: per hour. A higher boiling bottoms, 34.2 A.P.I. gravity, is withdrawn from the bottom ofntvower 168 through conduit 194, pump 196, land conduit 198 and 2 18 at a rate of approximatelyV 260,000 pounds per hour, passed to furnace 220 and returnedto the bottom of tower 168 by 6 tion base cut may be returned to the top of the towei through conduit 240 at a rate of approximately 285,000 pounds per hour, pump 242, and conduit 244. Another portion of the aviation base cut may be withdrawn through conduit 246 at a rate of approximately 366,000 pounds per hour and sent to storage. A post-aviation gas cut, 29.0 A.P.I. gravity, is withdrawn from the bottom j of xylene tower 202' through conduit 224, pump 226, and

conduit 228, and passed to conventional heating furnace 220 at a rate ofV approximately 578,000 pounds per hour and then returned to the Vbottom of the xylene tower 202 at a temperature ofapproximately 385 F. and a pressure ofapproximately 28 pounds gauge by conduit 230. Another'portion of the post-aviation gas may be withdrawn through conduit 232 ata rate of 16,000 pounds perhour and sent to storage. Although it is not specifically shown in the drawing, the post-aviation conduit 222 at a temperature of approximately 360 F. D

and a pressure of approximately' 41 pounds gauge. Another portion of the high boiling fraction in conduit 198 is sent to tower 202 by conduit 200 at a rate of approximately 96,000 pounds per hour referred to as a xylene splitter tower. AnV aviation base cut is withdrawn from vthe top of tower 202 by conduit 234, cooler 236, and passed to separator Y238'maintaine'datV a Vtemperature of approximately 250 F. and a pressure of approximately 0 pounds gauge. A portion of .this avia- .gasoline blending stock. .quired aviation blending material, it was necessary to cut may be used as a sponge oil in absorber column 124 to scrub the entrained lean oil constituents contained in the recycle gases ortail gases passed thereto by conduit 122.v

EXAMPLE 1 The basic design of a iiuid hydroforming process was set by the overall requirement for a Vhighgquality aviation In order to produce the rereform a select, narrow boilingv range (224-272 F.) naphtha at a high severity. Run I was continued for 42 days. Run Il was started and continued with excellent success. As the carbon and sulfur content of the catalyst was lowered to reasonable'levels, vattributed to good catalyst circulation, the eiective activity of the catalyst improved. After days of operation, aviation gasoline of the desiredoctane rating was'continuously produced in the process as shown in the drawing.

The tables (II through VIII) indicate the operation of the specific equipment shown in the drawing in accordance with this invention and indicates the successful operation and results that are obtained by absorption with a heavy Ynaphtha of valuable hydrocarbons from the tail gas of the process shown in the drawing. These tables are actual working examples of an operation using specific conditions of operation to achieve the various products shown in the drawing and more specifically identified in the tables.

TABLE I Operating conditions-Run II Number days. 8 15 15 15 Feed rate, b.p.d 17, 790 18, 300 18, 880 18, 550 Reactor temp., F 920 911 908 906 Cat. to oil ratio 0. 87 0.75 0.84 0.74 0. 77 Space velocity, W./hr./w 0. 34 0. 35 0.34 0.35 0. 33 Reactor pressure, p.s.i.g.' 225 225 225 225 225 C5|hydr0tormate oct., F-l (clear) 93. 4 92. 2 92.0 90. 9 90. 6 Recycle gas, s.c.f./b 5, 480 5, 410 5, 330 5, 5, 160 Mol percent H 67. 5 64.0 66. 1 66. 6 66. 2 Rec. gas furnace out, F 1, 154 1, 171 1, 157 1, 152 1, 148 Naphtha furnace out, F- 961 962 951 947 936 Carbon on cat., weight percent:

Spent-- 0. 59 0.70 0. 66 0. 74 0.71

Room-oratori 0. 02 0. 03 0. 04 O. 06 0. 05 Sulfur on spent cat., Weight percent 0. 05 0. 07 0.07 0.10 0.04 Reactor bed height, it.1 46. 5 45. 0 46. 0 44. 5 45. 5 Catalyst holdup, M lbs.:

Reactor- 571. 0 563. 0 594. 0 592. 0 616. 0

Regenerator 10. 3 11. 9 9. 8 10. 0 16. 4

Total 2- 601. 3 594. 9 623. 8 622. 0 652. 4:

Reactor density, #/tt.3 43 46 47 48 Regenerator holdup time, min. 3. 68 4. .48 89 6. 23 Cat. circulation, #/hr 158, 000 Regen. temp., F--. 097 1 0 1, 102 Combustion air, #/hr 22, 610 Regen. density, i/ft."i 25 1 Feed above grid.

TABLE II Conversion of naphthenes Date Food stock, b.p.d,1---.-- 17, 730 17, 500 17,970 17, 600 18, 672 19,050 18, 220 Parans, vol. percen 43.2 44. 6 44. 1 44. 1 7.0 46. 3 4.0 Nanhthpmq 44.2 42. 8 43. 7 43. 7 41.8 41. o 41. 0 Aromatics 12. 6 12.6 12. 2 12. 2 11.2 12.7 15. 0 Pre-aviation, b.p.d 7, 250 6, 860 6, 825 6, 510 8, 266 8, 160 6, 490 Por., vol. percent.. 3.6 45. 5 45. 4 40. 5 42. 8 42. 2 42. 4 Naph 16.4 17. 5 14.5 18.2 16. 2 17.7 17.8 Arom 40.0 37.0 40.1 41.3 41.0 40.1 39.8 Aviation base, b./d.-- 3, 230 3,200 3, 010 2, 860 2, 619 2, 440 3,120 Par., v01. percent.. 15.2 12.2 12.1 9. 0 14. 7 20. 5 16.1 Naph 8.1 7. 3 8. 2 7. 2 6. 4 7. 8 6. 2 Arom 76. 7 80. 5 79. 7 83.8 78. 9 71. 7 77. 9 Post aviation, b.p.d 1, 955 2, 025 2, 280 2, 220 2, 861 3, 200 3, 450 Par., v01 percent.. 6.0 3.1 5.1 4.2 8.0 8.1 9.2 Naph 4.2 2.1 3.3 3.2 4.6 5.5 5.5 Arom-. 89. 8 94. 8 91.6 92. 6 87. 4 86. 4 85. 3 Polymer, b.p.d.2 288 288 324 270 279 285 270 Depentanized hydrofor. (as produced):

Paramus, b.p.d 3,768 3,573 3,580 2,920 4,150 4,206 3, 569 Naphfhnnpq 1, 533 1, 477 1, 312 1, 460 1, 640 1, 809 1, 543 Aromatics 7, 422 7, 323 7, 547 7, 410 s, 285 8, 070 8, 218 Uneonverted naph., percent. 20.0 19.7 16. 7 19.0 21. 0 23. 2 20.6 Naph. conversion, percent- 80. 80.3 83.3 81.0 79. 0 76.8 79. 4 Total C to E.P., b.p.d.- 14,055 13, 419 14,116 13,805 15,123 15, 513 14,727 octane on 05+ 89. 8 92.1. 91.4 92. 3 90. 0 90. 4 91. 3 05+ analysis:

Naph., vol. percent- 10. 9 11.0 9. 3 10. 6 10.8 11.7 10.5 A om 52. 8 54. 5 53. 5 53. 6 54.4 52.0 55. 8 Par. (by diff 36. 3 35. 5 37. 2 35.8 34. 8 36. 3 33. 7

1 Adjusted to 100% output basis. 2 Assumed 100% aromatic.

TABLE III Temperatures, F.: Tower 56 o erationractionator Top tower "ff". 106 p Lean 011 93 Flows, b.p.d.: Operation 42nd tray 195 TOP feuX 11,240 46th tray V 2.05 Slurry reiluX 33,840 Bottom tower 403 Decent 011 (polymer) 284 Reboiier out 467 Slurry return 275 Tower pressure, p.s.i.g 215 Temperatures, F.: 40 l I Tower top 3 00 Gas analyses (M.S.), M01. percent Feed Overheadv Tower bottom 399 l Slurry return 354 2.4 2 7 Reflux drum 106 67.5 68.1 11.8 12.3 Pressures, p.s.1.g.: g Tower 225 0j 6 0I 4 Reflux drum 1 215 gg gg Slurry settler 267 1.1 0.3 Catalyst C oneentration, #/gal.: 0.7 jg Decant 011 Trace 0.1 0.1 2.1 1.7 Slurry return None Polymer inspections: C: recovery, m01. percent 512 C4 recovery mol. percent 91. 3 Gravity, API 24.0 ASTM- I-BnP --F Tower 124 Operation-absorber 0 462 oo Flows: Actual De-ethanzer overhead, m.p.h. Not metered 563 Percent at 700 o F. 98.7 Sponge' 011, b.p.d. (post avlatlon) 1498 D d 2071) t Rich 011, b.p.d. 1658 St (aauge rea S u m error Tail gas mp'h 1984.3 TABLE IV 65 Flash drum 150 gas, m.p.h. 5.3

Tower operation-de-ethanz'zer Temperatures, F-

A t l tion Tower top 108 FIOWS c ua Opera Tower bottom 109 Fractlonator gas, m.p.h. 1950 .1 97

Sponge o1 1n Fractionator 11qu1d, b.p.d. 16,200 70 Drum 150 218 Leaupil, 1?-13-d- 7f 61000 Rich Oil out 103 Reboiler circulation, b.p.d 42,000 Bottoms, b.p.d. 22,251 Pressures, p.s.1.g.: t 4 Overhead, m.p.h. A Not metered TOWer 124 200 Reboiler duty, mm. B.t.u./hr. 43.92 75 y, Drum 150 24 34 i' Absorber Flash l Gas analyses (M.S.), Mol. percent 124 overdrum 150 l, n head N24-002 2.7 0.7 H2-; 69.1 11.7 C1 12.7 12.5 Oz- 0.1 0.2 18:3 353i 03+ 3.8 27.1 ic. 0.4 4.6 04- 0. 1 n0.-- 0.2 1.6 in. nos-. 0.2 cyclo C: 0.3 0.5 3.0

I TABLE `VI Y Tower 120 operaton-de-pentanzer l Actual Flows, b.p.d.:

f Feed 22,251 I -Reux :12,500 Reboiler 24,850 Overhead product 2,500 Reux ratio, mols reux/mol product 5.0

Temperatures, F.:

f Tower top 168 thftray 222 25th tray 387 Tower bottom l 410 I Reboiler outlet 452 Reflux drum 117V Tower pressurep.s.i.g 100 Reboiler duty, mm. B.t.u./hr 39.3 Trim coolerduty, mm. B.t.u./hr. 22.5 Net reboiler heat to tower, mm. B.t.u./hr 16.8 Overhead condenserduty, mm. B.t.u./hr 20.8

Overhead, m.p.h.: Y

' 1 :I 1.3 'C2-' 0.5 Cg-l- 1:4 f C3 1.8 f *C3-I4 83.4 iC4l 57.6 C4 0.4 "RC4 ViCk, 76.6 11C5 49.7 cyclo C5' 5.9 4.2

Bottoms inspections: API 44.3 1 ASTM- ...f I,.B.'P. `201 1.0%l 227 30% 242` 50% 258 l70% 276 f 90% 303 Dry point 336 l End point 365 R.V.P. f 0.9 F-l octane (clear) 91.0

TABLE VII Tower 168 operation-gasoline splitter Actual Flows, b.p.d.:

Feed! 13,751 .enRcuXA 16,150 Reboiler 22,500 Overhead product 7,942 '.i Reflux ratio, mols` reux/mol product 2.04.

i 10 Temperatures, F.: 'f Tower top 304 6th tray 327 26th tray 379 Tower bottom 391 Reboiler outlet 421 AReflux drum 184 Tower pressure, p.s.i.g 32 Reboiler duty, mm. B.t.u./hr 39.7 Overhead condenser duty, mm. B.t.u./hr. 45.2 Pre-aviation inspections (overhead):

API 51.8 ASTM- I.B.P. 192 10% 207 30% 216 50% 223 232 90% 244 Dry point 261 End point 307 R.V.P. 1.4 F-1 octane (clear) 78.1

TABLE VIII Tower 202 operation-xylene splitter Actual Flows, b.p.d.:

Feed 5,809 Reux 21,070 Reboiler 44,400 Overhead product 2,538 Bottoms product 3,271 Reflux ratio, mols reliux/ mol product 8.29 Temperatures, F.:

Tower top 320 13th tray 321 23d tray 327 Redux drum 183 Tower bottom 373 Reboiler outlet 409 Tower pressure, p.s.i.g 15.5 Reboiler duty, mm. B.t.u./hr 54.9 Overhead condenser duty, mm. B.t.u./hr. 59.0

Product inspections Avia.base Post-avia.

Gravity, API 37. 4 33. 0 ASTM:

I.B.P 273 302 10lr 274 308 300. 275 312 5o'7 27e 317 70?. '27e 322 007. 277 334 Dry Point" 278 End Point- 32o ase .V.P 0.2 0.1 Parans, Vol. Percent 20.8 8. 8 Nnnhthones 7. 7 5. 7 Total arnmatfs 71. 5 85.5

i Para xylene 22. 7

Meta xylene 27. O Ortho xylcne.- 6. Ethyl benzene l.

Various pumps, valves, and auxiliary equipment have l invention will become apparent to those skilled inthe art recovered depentanized liquid product from said second distillation zoneto said rst distillation zone as reliux thereto; passing the gaseous fraction thus obtained to an absorption zone; in said absorption zone contacting said gaseous fraction with a sponge oil to remove lean-oil constituents from said fraction; and recovering thus-enriched sponge oil as a product ofthe process.

. 2. The process, of claim 1 in. which the sponge oil comprises a naphtha havingan API gravity from about 50. to about 60.

3. The processof claimV 1in which the sponge oil comprises a post-aviation gasoline fraction.

4. A process for treating the reaction product of a hydrocarbon conversion process which comprises: separating said reaction product into a liquid product fraction and a gaseous fraction containing entrained liquid product; combining at least a portion of said gaseous fraction with at least a portion of said liquid product; separating the fractionsvthus combined into a gaseous fraction comprising lean-oil constituents and substantially free of components higher boiling than ethane and a liquid fraction comprising components higher boiling than ethane; passing the gaseous fraction thusobtained to an absorption zone; in said absorption zone contacting said gaseous fraction with a sponge oil to remove lean-oil constituents from said fraction; recovering thus-enriched sponge oil as a product of the process; passing said last-mentioned liquid fraction to a depentanizing zone; in said depentanizing `Zone separating said fraction into a low boiling fraction comprising components having less-than 6 carbon atoms per molecule and a high boiling fraction comprising components having at least 6 carbon atoms per molecule; passing a portion of said high boilingfraction from said depentanizing zone to said de-ethanizing zone as reux thereto; and passing said high boiling fraction to said absorption zone as an absorption medium.

5. The process of claim 4 in which a portion of said rst-mentioned gaseousv fraction is condensed and passed to said de-ethanizing step.

6. A process for treatingthe reaction product of a hydrocarbon conversion process'which comprises: passing combining at least a portion ofsaid gaseous fraction with,

at least a portion of said liquid product; separating; the fractions thus combined into a gaseous fraction comprising lean-oil constituents and substantially free of components higher boiling than ethane and a-liqud fraction comprising components higher boiling than ethane; passing the liquid fraction thus obtained to a second distillation zone; recovering a depentanized liquid product from said second distillation zone; passing a' portion of said recovered depentanized liquid product from said second distillation zone to said rst distillation zone as reux thereto; passing the gaseous fraction thus obtained to an absorption zone; in said absorption zone'contacting said gaseous fraction with a sponge oil at a temperature between about 110 F. and about 150 F. to remove lean-oil constituents from said fraction; and recovering thus-enriched sponge oil as a product of the process.

. 7. A process for treating thel reaction product of a hydrocarbon conversion process which comprises: passing said product to a separation zone; separating said reactionA 12 product in said zone at a temperature between aboutZSO- F. and about 300 F. into a liquid product fraction and a gaseous fraction containing entrained liquid product;

combining at least a portion of said gaseous fraction with `at least avportion of said liquid product; separating the fractions thus combined into a gaseous fraction comprising lean-oil constituents and substantially free of components higher boiling than ethane and a liquid fraction comprising .components higher boiling than ethane; passing the gaseous fraction thus obtained to an absorption zone; in said absorption zone contacting said gaseous fraction with a sponge oil at a temperature between aboutl F. and about 150 F. to remove lean-oilrconstituents, from said fraction; recovering thus-enriched spongeoilias aV product of the process; passing said last-mentionedliquid fraction to a depentanizing zone; in said depentanizing zone separating said fraction into a low boiling fraction comprising components having less than 6 carbon atoms per molecule and a high boiling fraction comprising components having at least 6 carbon atornsper molecule; passing a portion of said high boiling fraction from said depentanizing zone to said de-ethanizing zone as reux thereto; and passing said high boiling fraction to said absorptionzone as an absorption medium.

8. An improved integrated process for recovery of valuable products, which comprises hydroforrning a naphtha.. fraction in the presence of a hydroforming catalyst, recovering the hydroformate product and cooling the'same, passing the cooled hydroformate product to an initial separation zone, recovering a gaseous fraction containing entrained liquid product from the upper portion of said initial separation zone and liquid product from ,the lower portion thereof; passing a portion of said gaseous fraction.

containing entrained liquid product and said liquid prod-.

uct recovered from said initial separation step to aydis-U tillation zone reuxed with a product of the process hereinafter described, recovering a gaseous product from the upper portion of said distillation zone containing entrained liquid product, recovering liquid product from thelower portion of said distillationzone, passing said liquid product fromsaid rst distillation zone to a second distillation zone, recovering a, depentanized liquidproduct from said second distillation zone, passing a portion of said re- Covered depentanized liquid product to saidrst distillatiorrzone as reflux thereto, passing another. portion of said depentanized liquid product to further separation to recover gasoline products, passing said gaseous fraction containing entrained liquid product recovered fromsaid iirst distillationzone to an absorption zone, in said absorption zone contacting said gaseous fraction containing entrained liquid with a gasoline product of the process to absorb said entrained liquid, and ,recovering said e11-v riched gasoline as a product of the process. Y

9. A hydroforming process which comprises passing a. naphtha feed in contact with a hydroformingcatalyst to convert the naphtha into valuable hydroformate product, passing said hydroformate product to an initial 'separation Zone operated at a temperature in the range of from about 250to about 300 F. and a pressure of about 245 p.s.i.g., separating said hydroformate product in said initial separation zone into a liquid fraction and a gaseous fraction containing entrained liquid product, combining a portion of said gaseous fraction containing entrained liquid product with said liquid fraction, passing said combined yfraction to a de-ethanizer zone operated at a temperature in the range of from about 110 F. to about 400 F. and a pressure of about `210 to 230Vp.s.i.g., to eiect separation of a gaseous product containing entrained liquid product from` the liquid hydroformate product, recovering taily 13 A a depentanized liquid product from the lower portion of said depentanizer zone, passing a portion of said depentanized liquid product to the upper portion of said deethanizer zone as reux thereto, passing another portion of said depentanized liquid product to further separation to recover a post-aviation gasoline fraction, passing a portion of said' post-aviati0n gasoline fraction to an absorption zone, passing said gaseous fraction containing entrained liquid product recovered from said de-ethanizer zone to said absorption zone, in said absorption zone contacting said gaseous fraction containing entraned liquid product with said gasoline fraction to absorb entrained liquid product of said gaseous fraction, said absorption zone being operated lin a temperature range of about 110 F. to about 150 F., recovering a gaseous fraction substantially free of entrained liquid product from the upper portion of said absorption zone, and recovering an enriched gasoline fraction from the lower portion of said absorption zone as a product of the process.

References Cited in the tile of this patent UNITED STATES PATENTS 2,398,674 Schulze Apr. 16, 1946 2,719,816 Rich Cct. 4, 1955 2,733,192 Sage Ian. 31, 1956 2,805,979 Vermilion Sept. 10, 1957 

1. A PROCESS FOR TREATING THE REACTION PRODUCT OF A HYDROCARBON CONVERSION PROCESS WHICH COMPRISES: SEPARATING SAID REACTION PRODUCT INTO A LIQUID PRODUCT FRACTION AND A GASEOUS FRACTION CONTAINING ENTRAINED LIQUID PRODUCT; COMBINING AT LEAST A PORTION OF SAID GASEOUS FRACTION WITH AT LEAST A PORTION OF SAID LIQUID PRODUCT; SEPARATING THE FRACTIONS THUS COMBINED INTO A GASEOUS FRACTION COMPRISING LEAN-OIL CONSTITUENTS AND SUBSTANTIALLY FREE OF COMPONENTS HIGHER BOILING THAN ETHANE AND A LIQUID FRACTION COMPRISING COMPONENTS HIGHER BOILING THAN ETHANE; PASSING THE LIQUID FRACTION THUS OBTAINED TO A SECOND DISTILLATION ZONE; RECOVERING A DEPENTANIZED LIQUID PRODUCT FROM SAID SECOND DISTILLATION ZONE; PASSING A PORTION OF SAID 